1. Technical Field of the Invention
The present invention relates to information exchange between a connected electronic device and a battery, and more particularly, to the identification of and communication with an attached battery by an electronic device.
2. Description of Related Art
The development of cellular telephone technology has spurred a like need for development in the area of batteries and battery packs, and more specifically, for methods of communicating between a battery and an electronic device, such as a cellular telephone. Cellular telephones must utilize batteries in order to provide mobile capabilities. The battery is critical to the user of a cellular telephone, since the battery provides them with the ability to move about freely without being tied to a stationary power source.
Thus, in order to fully maximize the use of a cellular telephone, it is important that a user achieve maximum performance from an attached battery. This may be achieved by correctly charging the battery and always being able to identify the exact charging status of the battery. This enables a user to know how much standby time is remaining on the phone. This type of information enables the user to intelligently decide if the charge in a battery is sufficient for their needs or charging of the battery is required.
Developments of battery and battery pack related technologies have provided users with a variety of batteries which may be used with an electronic device, such as a cellular telephone. Users may have so-called xe2x80x9cdumbxe2x80x9d, low-end batteries which merely provide a source of power to an electronic device and no further information. These batteries may not communicate with other devices. These type of batteries have a relatively low cost and are simple to use. The so-called xe2x80x9csmartxe2x80x9d batteries provide a user with a power source for an electronic device and further provide data transmission capabilities between the battery and the attached electronic device. A xe2x80x9csuper smartxe2x80x9d battery may communicate with an attached electronic device exactly what the present charge status of the battery is and can calculate this information internally without any additional input from the attached electronic device. A xe2x80x9csmartxe2x80x9d battery may communicate with an attached electronic device and includes registers for storing information on the capacity of the battery.
Cellular telephones require the ability to operate with xe2x80x9csuper smartxe2x80x9d, xe2x80x9csmartxe2x80x9d and xe2x80x9cdumbxe2x80x9d batteries in order to fully utilize all technologies available. However, there presently exist no type of interface between a battery and electronic device that enables the identification of the particular type of battery attached to the electronic device, and further enables communications between the battery and the electronic device if the attached battery is identified as a xe2x80x9csmartxe2x80x9d battery. Furthermore, in the case of xe2x80x9cdumbxe2x80x9d batteries, there is a the need to provide a user of an electronic device with information identifying the amount of charge/standby time currently available to the user based on the current charge within the battery.
Existing battery communication systems have been developed for use with personal computers. These battery communication systems, while satisfactory for a personal computer operating environment, are too complex and expensive for use with smaller and cheaper electronic devices, such as a cellular telephone. Furthermore, such systems do not include the ability to operate with xe2x80x9cdumbxe2x80x9d batteries. Thus, there exist a need for a system overcoming these limitations.
The present invention overcomes the foregoing and other problems with an apparatus for supporting resistor keying and communications between a battery and an electronic device over an interface. The apparatus of the present invention enables a connection to be formed between a processor within an electronic device and a battery or battery pack. Circuitry within the electronic device enables the electronic device to determine what type of battery has been connected with the electronic device. The circuitry may comprise switches and a resistor or current source that work in conjunction with the processor to determine an exact resistance or capacitance value of a resistor or capacitor between the single pin interface and the ground pin. The resistance or capacitance value corresponds to a battery type.
Once the battery type is identified, if a xe2x80x9csmartxe2x80x9d battery is connected to the electronic device, the processor of the electronic device may communicate with the battery through a communications interface consisting of a transceiver and a pair of data registers. Data to be transmitted to the battery is written to a data-out register and then transmitted by the transceiver to the communications circuitry of the battery over a single pin interface. Data coming back from the communications circuitry of the battery pack is received by the transceiver and temporarily stored within a data-in register. The information remains in the data-in register until read by the processor.
In the case of a battery identified as a xe2x80x9cdumbxe2x80x9d battery (i.e., incapable of performing data communications with the electronic device), the battery may further include a first and second memory storage areas. The first memory storage area contains a numeric representation of the total capacity of the battery. The second memory stores a numeric representation of the current capacity of the battery. Upon connection of the battery to the electronic device, the numeric representation within the second memory is altered by the electronic device in response to the use or charging of the battery. Utilizing the numeric representation information from each of the memory storage areas, the processor associated with the electronic device may determine the charge capacity of the battery. For example, the system may determine whether the battery is half charged, full charged or quarter charged, much in the same way a fuel gauge provides information to the driver of an automobile.